Rear vision system for a vehicle equipped with a vehicle communication network

ABSTRACT

A vehicle rear vision system includes at least two rearview assemblies each having an image transfer device for transferring images rearwardly of the vehicle in order to be observable by a driver. A rear vision communication system is provided to effect communication between the rearview assemblies. The rear vision communication system also includes a communication link with the vehicle multiplex communication network. The vehicle rear vision system may include an interactive dynamic position control, which repositions each mirror in the system in response to a change in the position of one mirror in a manner which allows the mirror aim to track a driver&#39;s eye position.

BACKGROUND OF THE INVENTION

[0001] This invention relates generally to vehicle rear vision systemsfor providing drivers with a view rearwardly of the vehicle. Theinvention may find application with optical rearview mirror assembliesand with solid-state-imaging arrays which capture images rearwardly ofthe vehicle for display by a display device.

[0002] With the advent of electro-optic mirror systems, in which anelectro-optic reflectance element is driven to a partial reflectancelevel by a control module which is responsive to light levels in andaround the vehicle, the vehicle rearview mirror has become an electronicassembly. Additional elements, such as motorized positioning devices, oractuators, for the mirror as well as mirror heaters, further contributeto the electrical functions performed by a mirror assembly. Thesefunctions require a one-way flow of control information to the mirrorassembly. More recent features, such as multiple mirror position memory,require a two-way communication flow. The memory mirror assemblyincludes a position encoder which communicates the position of themirror to a memory controller, typically located remotely from themirror, such as at the vehicle dash. Other two-way communication flowsare required by the addition of other features in the rearview mirror,such as keyless entry systems and the like. Other features are beingadded to vehicle mirrors, in general, and exterior mirrors, inparticular, such as remote-actuated exterior vehicle security lights andsignal lights, such as disclosed in commonly assigned U.S. Pat. Nos.5,371,659 and 5,497,305 for REMOTE ACTUATED EXTERIOR VEHICLE SECURITYLIGHT; global positioning system antennas and/or receivers, as disclosedin commonly assigned U.S. patent application Ser. No. 08/569,851 filedDec. 8, 1995, by Roger L. Veldman and Desmond J. O'Farrell for a VEHICLEGLOBAL POSITIONING SYSTEM NAVIGATIONAL AID; and blind spot detectionsystems, such as disclosed in U.S. patent application Ser. No.60/013,941 filed Mar. 22, 1996, by Kenneth (NMI) Schofield for PROXIMITYDETECTION OF OBJECTS IN AND AROUND A VEHICLE, the disclosures of whichare hereby incorporated herein by reference. Various other electronicfunctions, including heading sensors, better known as electroniccompasses, intrusion detection and other security systems, antennas forintelligent vehicle highway systems (IVHS), as well as varioustransmitting and/or receiving antennas and/or systems including garagedoor openers, cellular telephones, radios, and the like are candidatesfor positioning within a mirror assembly.

[0003] Even with the moderate level of electrification of presentvehicle mirror assemblies, it is not uncommon to require as many as 20wire leads extending to the exterior mirror assemblies. This creates theproblem of guiding the wire harness, including a connector, through thedoor panel. Additionally, the wiring harness adds weight to the vehicleand greatly increases the labor assembly time of the vehicle.

[0004] It has been proposed to replace the exterior mirror system of avehicle with solid-state-imaging arrays which capture images rearwardlyof the vehicle for display by a display device on or near the vehicledash. One such system is disclosed in commonly assigned U.S. patentapplication Ser. No. 08/445,527 filed May 22, 1995, by Kenneth (NMI)Schofield, Mark L. Larson and Keith J. Vadas for a REARVIEW VISIONSYSTEM FOR VEHICLE INCLUDING PANORAMIC VIEW, the disclosure of which ishereby incorporated herein by reference. In such a rearview visionsystem, the solid-state-imaging device may be positioned in a housing inthe approximate vicinity of present exterior rearview mirrors. As such,it can be expected that many of the electrical functions being placed inthe housing of existing and proposed rearview mirror assemblies will beplaced in the housing of the solid-state-imaging array in such system.

[0005] The increase in electronic functions being performed through thevehicle rearview assembly increasing involves communication with otherportions of the vehicle. For example, global positioning system (GPS)functions and intelligent vehicle highway system (IVHS) functions mayinteract with other modules controlling vehicle navigation and the like.A headlamp control of the type disclosed in commonly assigned U.S.patent application Ser. No. 08/277,674 filed Jul. 19, 1994, by KennethL. Schierbeek and Niall R. Lynam, for an AUTOMATIC REARVIEW MIRRORSYSTEM WITH AUTOMATIC HEADLIGHT ACTIVATION, the disclosure of which ishereby incorporated herein by reference, utilizes common light sensorsfor activating the vehicle's headlights and establishing a partialreflectance level for the electro-optic mirror element. Such featurerequires interaction with a headlamp module. Keyless entry systems mayinteract wish the vehicle door locks, as well as interior lightingsystems. Blind spot detection, intrusion detection, as well as numerousother functions, may involve interaction with various modules associatedwith the vehicle dash. Therefore, the vehicle mirror system is becomingmore integrated with the rest of the vehicle electronics. A variety ofother functions can be integrated into the interior or exterior mirrorhousing. For example, an electronically trainable garage door opener maybe included, such as is described in U.S. Pat. No. 5,479,155 issued toZeinstra et al.

[0006] In order to minimize hardware cost and overhead, as well asprovide flexibility for expansion and technological advancements invehicle electronics, vehicles are increasingly being equipped withserial data communication networks. Such networks include abidirectional serial multiplex communication link over a bus among aplurality of control modules, each containing a microprocessor ormicrocomputer. Messages are transmitted asynchronously with prioritiesassigned to particular messages. For example, messages which requireimmediate access to the bus for safety reasons are provided toppriority, with messages that require prompt action in order to preventsevere mechanical damage to the vehicle provided with a lesser prioritybut a higher priority than messages that affect the economical orefficient operation of the vehicle. The protocol of the system providesthat higher priority messages are communicated without delay while lowerpriority messages await communication of higher priority messages. Anindustry standard for such serial data communication network is SAEJ1708published October, 1993.

[0007] Functions associated with rearview mirror assemblies havetraditionally not been included on the vehicle communication network.Almost all of the traditional mirror functions would be assigned lowestpriority and would, therefore, have to await transmission of higherpriority messages. Therefore, the traditional approach has been toprovide dedicated hardware interconnects between devices located in therearview mirror assemblies and external devices, such as power sources,switches, controls, and the like. One solution is proposed in U.S. Pat.No. 5,196,965 entitled REARVIEW UNIT FOR MOTOR VEHICLES in which amultiplex data system communicates information between a control unitand at least one exterior rearview mirror. While such system reduces thewire count extending through the door, or doors, to the exteriormirrors, it fails to fully integrate functions associated with themirror assemblies with the remaining electronic assemblies of thevehicle.

[0008] Vehicle memory mirror systems include encoders for monitoring theposition of each mirror element with respect to typically two axes and apositioning device, such as an actuator, for selectively positioninigthe mirror element with respect to those axes. A control unit, typicallylocated in and about the dash or in the door assembly, is capable ofstoring multiple data sets, each of which establishes a particularposition of one or more of the vehicle's mirror elements. In thismanner, when a different driver operates the vehicle, the data setassociated with the driver is retrieved and utilized to position themirror element, or elements, according to that data set. In order to doso, it is necessary to have information regarding the actual position ofthe mirror, which is provided by the position encoder, in order toenable the control to properly position the mirror element or elements.Such memory mirror systems further contribute to the wiring problemassociated with rearview mirrors. The signals from the position encoderrequire additional wire leads, and all mirror assemblies included in thesystem must be wired back to a processor which is typically located inthe dash. Furthermore, a user input device, such as a joystick, must beprovided for use with each of the mirror elements of the memory mirrorsystem in order to allow each driver to adjust each mirror element andstore the position of that mirror element for that driver. This is arather cumbersome process that can be distractive if performed while thevehicle is being operated.

SUMMARY OF THE INVENTION

[0009] The present invention is directed to a vehicle rear vision systemhaving at least two rearview assemblies. Each of the rearview assembliesincludes an image transfer device for transferring images rearwardly ofthe vehicle in order to be observable by a vehicle driver and a housingfor the image transfer device. According to an aspect of the invention,a rear vision communication system provides communication between therearview assemblies. Additionally, the rear vision communication systemincludes a communication link with the vehicle communication network.The rear vision communication system preferably includes control modulesin each of the rearview assemblies which are interconnected by acommunication channel. The image transfer device may be a mirrorelement, preferably an electro-optic mirror element and, mostpreferably, an electrochromic mirror element. Alternatively, the mirrorelement could be a chrome mirror or a standard silvered day/nightprismatic mirror, especially for the interior rearview assembly.Alternatively, the image transfer device may be a solid-state-imagingarray which captures images rearwardly of the vehicle for display by adisplay device.

[0010] According to a somewhat more specific aspect of the invention, avehicle rear vision system includes an interior rearview mirror assemblyand at least one exterior rearview mirror assembly, each including anelectro-optic reflectance element and a housing for the reflectanceelement. The interior rearview mirror assembly includes amicroprocessor-based control having a control channel to establish apartial reflectance level of the associated electro-optic reflectanceelement The exterior rearview mirror assembly includes amicroprocessor-based control having a first control channel to establisha partial reflectance level of the associated electro-optic reflectanceelement, a second control channel to selectively activate a heaterelement in heat transfer association with the associated electro-opticreflectance element, a third control channel to operate a positioningdevice for the associated electro-optic reflection element, and a fourthcontrol channel for receiving positional data from an encoder coupledwith the associated electro-optic reflectance element. A communicationchannel is provided interconnecting the microprocessor-based controls,defining a rear vision communication network. At least one of themicroprocessor-based controls includes a hardware node configured tointerconnect with the vehicle communication network. That particularmicroprocessor-based control is programmed to format messages for thevehicle communication network and decode messages from the vehiclecommunication network.

[0011] Such a vehicle rear vision system, including a rear visioncommunication network, enhances the functionality of the vehicle rearvision system because the control commands for strictly local functionsassociated with the rear vision system are handled without requiringaccess to the vehicle communication network. In this manner, the rearvision system functions do not need to compete with higher priorityfunctions of the vehicle communication network, such as automaticbraking systems, air bag systems, and the like. This additionallyreduces the load on the vehicle communication network by reducing thenumber of messages processed on that network. A vehicle rear visionsystem, according to the invention, provides connectivity betweenfunctions carried out by the vehicle rear vision system and otherportions of the vehicle electronic system. This is provided by thecommunication link between the rear vision communication network and thevehicle communication network. This is accomplished without requiring alink between each rearview assembly control module and the vehiclecommunication network. Not only does this enhance the functionality ofthe vehicle rear vision system and the vehicle communication network, itreduces system hardware and software expense because most rearviewassemblies require only a communication module and associated software.Only one of the rearview assemblies must be fully compatible with thevehicle communication network. A vehicle rear vision system, accordingto the invention, also significantly reduces the number of wire runs toeach rearview assembly which reduces weight and cost while concurrentlyfacilitating enhancement in reliability.

[0012] A vehicle rear vision system, according to yet an additionalaspect of the invention, includes a plurality of rearview mirrorassemblies, each including a reflective element, an actuator, whichadjustably positions the reflective element about at least one axis, anda position encoder, which monitors the position of the reflectiveelement with respect to that axis. A control is provided which isresponsive to the encoder for each mirror assembly in order to supplypositioning signals to the actuator for that mirror assembly. Thepositioning signals are a function of the position of the reflectiveelement of that mirror assembly. The positioning signals areadditionally a function of the position of the reflective element of atleast one other of the mirror assemblies. Because each mirror reflectiveelement is positioned by its actuator as a function not only of its ownposition, but the position of one or more of the other mirror reflectiveelements, a change in position of one reflective element results in arepositioning of all of the reflective elements controlled in thismanner. This interactive dynamic memory mirror system is capable ofdefining a unique position, associated with the driver's eyes, which istargeted by all mirrors as a viewing point. As the viewing pointchanges, the position of the mirrors change in unison. Thus, this aspectof the invention provides an active closed-loop system which correlatesthe position of all mirror reflective elements. The user viewing pointmay be established by a conventional user input device, such as ajoystick, such that manipulation of the joystick allows the user tosimultaneously reposition all of the system mirror elements. Thisreduces the amount of manipulation which must be carried out by thedriver to position the mirrors according to the viewing point of thatdriver. Additionally, a reduction in system hardware may be effectedbecause only one joystick circuit is required. This aspect of theinvention also comprehends the elimination of the joystick altogether byallowing the driver to position one mirror reflective element, such asthe interior mirror reflective element, by hand with the controlinteractively repositioning the other mirror elements in response to themanual repositioning of the mirror reflective element. Alternatively,the location of the driver's eyes and, therefore, the optimum viewingpoint for each of the mirror elements, may be measured by machine visiontechniques using solid-state-imaging arrays and image recognitionsoftware known in the art.

[0013] A dynamic interactive memory mirror system, according to thisaspect of the invention, may additionally include a “zeroing” functionin order to allow the driver to establish an initial positionalrelationship of the mirror elements that is more suitable to thatdriver. This would be particularly advantageous for drivers who utilizeunconventional seating postures. The positional relationships of themirror elements may be fixed to a more desirable viewing angle withrespect to the vehicle than is typically utilized by most drivers. Forexample, it is known that most drivers align exterior rearview mirrorsin order to capture at least a portion of the side of the vehicle in theimage viewed in the mirror element by the driver. However, a mirrorelement orientation which extends angularly more outwardly of thevehicle may be more optimal for capturing objects in the drive'straditional blind spot. By pre-establishing positional relationshipsbetween the mirror elements, it may be possible to position the exteriormirrors in more appropriate positions with respect to the position ofthe interior mirror than that which would be typically set by the driverutilizing conventional norms. These and other objects, advantages, andfeatures of this invention will become apparent upon review of thefollowing specification in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014]FIG. 1 is a top plan view of a vehicle incorporating theinvention;

[0015]FIG. 2 is a block diagram of a rear vision communication system,according to the invention;

[0016]FIG. 3 is a first embodiment of a vehicle rear vision systemincorporating the invention;

[0017]FIG. 4 is an alternative embodiment of a vehicle rear visionsystem;

[0018]FIG. 5 is a block diagram of a control module;

[0019]FIG. 6 is an alternative embodiment of a rear vision communicationsystem;

[0020]FIG. 7 is another alternative embodiment of a rear visioncommunication system; and

[0021]FIG. 3 is a top plan view of an interactive mirror system,according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0022] Referring now specifically to the drawings, and the illustrativeembodiments depicted therein, a vehicle 15 is shown having a vehiclerear vision system 16, including an interior rearview assembly 18 and apair of exterior rearview assemblies 20 (FIG. 1). In the illustratedembodiment, interior rearview assembly 18 is an interior rearview mirrorwhich is preferably an electrically operated optical device and, mostpreferably, an electro-optic mirror, such as an electrochromic mirror, aliquid crystal mirror, or the like. Exterior rearview assemblies 20 maybe exterior rearview mirror assemblies which are preferably electricallyoperated optical devices and, most preferably, electro-optic mirrors,such as an electrochromic mirror or a liquid crystal mirror, or thelike, of the type disclosed in U.S. Pat. No. 5,371,659 entitled REMOTEACTUATED EXTERIOR VEHICLE SECURITY LIGHT, the disclosure of which ishereby incorporated herein by reference. Alternatively, exteriorrearview assemblies 20 and, possibly, interior rearview assembly 18 maybe image transfer devices incorporating a solid-state-imaging arraywhich captures images rearwardly of the vehicle for display by a displaydevice (not shown), as disclosed in commonly assigned U.S. patentapplication Ser. No. 08/1445,527 filed May 22, 1995, by Kenneth (NMI)Schofield, Mark L. Larson, and Keith J. Vadas for a REARVIEW VISIONSYSTEM FOR VEHICLE INCLUDING PANORAMIC VIEW, the disclosure of which ishereby incorporated herein by reference.

[0023] Vehicle rear vision system 16 includes a rear visioncommunication system 22 having one or more control modules 24, each ofwhich is associated with interior rearview assembly 18 or an exteriorrearview assembly 20 (FIG. 2). Rear vision communication system 22further includes an interface and control module 26, which may beassociated with interior rearview assembly 18, or an exterior rearviewassembly 20, and which is interconnected with control modules 24 by acommunication channel illustrated at 28. In addition to being linkedwith control module(s) 24, interface and control module 26 is linkedwith a vehicle-multiplexed communication network 30 provided withvehicle 15. Such vehicle-multiplexed communication network is typicallyproprietary to the manufacturer of the vehicle but is supplied accordingto industry standards, such as SAEJ1708 dated October, 1993, entitledSERIAL DATA COMMUNICATION BETWEEN MICROCOMPUTER SYSTEMS IN HEAVY-DUTYVEHICLE APPLICATIONS, the disclosure of which is hereby incorporatedherein by reference.

[0024] In one embodiment, communication channel 23 at rear visioncommunication system 22 is a bidirectional, multiplex serialcommunication link, as illustrated in FIG. 6, that is supplied accordingto industry standards for serial data communications, such as SAEJ1708issued October, 1993. As such, communication channel 23 preferably isdefined by a pair of conductors including a redundant pair ofconductors. Each control module 24 and interface and control module 26includes a serial bus data node 32. Communication channel 28 isinterfaced in hardware with each control module 24 and interface andcontrol module 26 through the associated data node 32. Interface andcontrol module 26 includes an additional node serial bus 32 for linkingwith the vehicle-multiplexed communication network 30. Nodes 32 arehardware-defined receiver or transceiver circuits complying with RS-485protocol as defined in SAEJ1708 or other suitable communicationprotocol.

[0025] Alternatively, communication channel 28′ could be defined by afiber-optic cable having either a glass or plastic fiber with nodeswhich are capable of interfacing such fiber-optic system with controlmodules 24 and interface and control module 26. Alternatively,communication channel 28′ could be a radio frequency (RF) link; in whichcase, the nodes would be capable of interfacing the RF link with controlmodules 24 and interface and control module 26. Alternatively,communication channel 28 may be defined by superimposing communicationsignals on the vehicle DC power grid, a technique generally referred toas carrier-current modulation, as well as other known techniques fortransmitting data.

[0026] An alternative rear vision communication system 22′ isillustrated in FIG. 7. System 22′ utilizes a communication channel 28′defined by a plurality of separate leads 34 providing interconnectionsbetween interface and control module 26′ and each control module 24′without requiring a serial bus data node, although such node could beused to improve transmission over longer distances. Communicationchannel 28′ could be a non-multiplexed system in which interface andcontrol module 26′ regulates communication with each control module 24′.As such, communication from one control module 24′ to the other controlmodule 24′ would take place under the control of interface and controlmodule 26′. However, interface and control module 26′ includes a serialbus data node 32 linking the rear vision communication system 22′ withvehicle-multiplexed communication network 30.

[0027] Rear vision communication system 22 can communicate betweenmodules in the rear vision system according to any protocol that issuited to the application, as would be readily apparent to those skilledin the art. Preferably, rear vision communication system 22 would complywith industry standards, such as SAEJ1708 (OCT93), which is the typicalstandard utilized for vehicle-multiplexed communication network 30.Because it is a separate and distinct communication system, rear visioncommunication system 22 can utilize its own message definition andpriority which can be consistent irrespective of the proprietaryprotocol utilized with the vehicle-multiplexed communication network towhich the rear vision communication system is linked. In this manner,only the software of the interface and control module 26 must be adaptedto the particular proprietary protocol of the vehicle. The remaininghardware and software of rear vision communication system 22 would beuniform irrespective of the particular vehicle. Rear visioncommunication system 22 may use other network configurations such as theNovell 10-Base-T hub-and-spoke architecture, or the like.

[0028] As can be seen in FIGS. 3 and 4, each control module 24 orinterface and control module 26 is positioned within interior rearviewassembly 18 or one of exterior rearview assemblies 20. In particular,the respective control module or interface and control module ispositioned within a housing 36 of the respective rearview assembly. Inthe embodiment illustrated in FIG. 3, vehicle vision system 16incorporates interface and control module 26 in an exterior rearviewassembly 20. In this manner, the link with vehicle-multiplexedcommunication network 30 is made at the corresponding exterior rearviewassembly 20. In an alternative embodiment illustrated in FIG. 4, vehiclerear vision 16′ incorporates interface and control module 26 within thehousing 36 of interior rearview assembly 18. In this manner, the linkwith vehicle-multiplexed communication network 30 is made at theinterior rearview assembly for vehicle rear vision system 16′.

[0029] A representative interface and control module 26 is illustratedin FIG. 5. Interface and control module 26 includes a microcomputer 38and a pair of serial bus data nodes 32. One node 32 is connected withcommunication channel 28, and the other is connected withvehicle-multiplexed communication network 30. Microcomputer 38 isinterconnected with one or more input and/or output devices, asillustrated in FIG. 5. It should be understood that the particular inputand/or output devices interconnected with microcomputer 33 may varydepending upon the particular features provided with vehicle 15 and thelocation of interface and control module 26. If interface and controlmodule 26 is positioned within interior rearview assembly 18, the inputand/or output devices would likely be different than if interface andcontrol module 26 is positioned within the housing of exterior rearviewassembly 20. It should additionally be understood that a control module24 is similar to interface and control module 26, except that serial busdata node 32 extending to the vehicle-multiplexed communication networkwould not be provided for the control module.

[0030] By reference to FIG. 5, interface and control module 26 mayprovide an output to an actuator 40 and receive an input from a positionencoder 42, both of which are mechanically coupled with a mirrorreflectance element, generally illustrated at 44. In this manner,microcomputer 38 provides outputs to operate actuator 40 and receivespositional data from encoder 42 as an input. Interface and controlmodule 26 may additionally receive an input from one or more lightsensors 46. The level of light to which light sensors 46 are exposed maybe utilized by microcomputer 33 in order to provide an output to anelectro-optic element 48 in order to establish the partial reflectancelevel of the electro-optic element and/or may be utilized to provide anoutput over vehicle-multiplexed communication bus 30 to a headlightcontrol module (not shown) in order to activate the vehicle headlightsin low light conditions and deactivate the vehicle headlights in highlight conditions, both functions are disclosed in commonly assigned U.S.patent application Ser. No. 08/277,674 filed on Jul. 19, 1994, byKenneth L. Schierbeek and Niall R Lynam for an AUTOMATIC REARVIEW MIRRORSYSTEM WITH AUTOMATIC HEADLIGHT ACTIVATION, the disclosure of which ishereby incorporated herein by reference.

[0031] Microcomputer 38 may additionally provide an output in order toactuate a security light 50 and/or a turn and/or stop signal 52 of thetype disclosed in commonly assigned U.S. Pat. No. 5,371,659 entitledREMOTE ACTUATED EXTERIOR VEHICLE SECURITY LIGHT, the disclosure of whichis hereby incorporated herein by reference. The signal to actuatesecurity light 50 may be received as an input from a keyless entryantenna 54. Instead of merely a keyless entry antenna, device 54 may bean entire keyless entry receiver system including antenna and receiver.Microcomputer 38 may additionally provide an output to a heater 56 whichis in heat transfer association with reflective element 44. Heater 56may be of the type disclosed in commonly assigned U.S. Pat. No.5,446,576 for an ELECTROCHROMIC MIRROR FOR VEHICLE WITH ILLUMINATIONCONTROL, the disclosure of which is hereby incorporated herein byreference.

[0032] The previously described functions performed by microcomputer 38involve primarily mirror-related functions or one-way communicationsprovided from an input device or to an output device. As can be seen,for example, with respect to control of the activation state of thevehicle headlights, the input provided to microcomputer 38 may becommunicated over the vehicle-multiplexed communication bus 30 to othermodules on the vehicle bus. Likewise, communication with other moduleson the vehicle bus may be two-way communication. For example, a blindspot detector 58 may provide inputs to, and receive outputs from,microcomputer 38 which are then communicated through vehiclecommunication bus 30 to other vehicle control modules. Interface andcontrol module 26 may additionally include a global positioning system(GPS) antenna 60, or entire GPS receiver assembly including the receiverelectronics associated with the antenna, which provides an input to, andreceives an output from, microcomputer 38 as disclosed in commonlyassigned U.S. patent application Ser. No. 08/569,851 filed Dec. 8, 1995,by Roger L. Veldman and Desmond J. O'Farrell for a VEHICLE GLOBALPOSITIONING SYSTEM NAVIGATIONAL AID, the disclosure of which is herebyincorporated herein by reference. In a similar fashion, interface andcontrol module 26 may include two-way communication with an intelligentvehicle highway system (IVHS) transceiver 62 in order to receive IVHSinput data, and to transmit IVHS output data, as is known in the art.Interface and control module 26 may include an output to a garage dooropener antenna 64, or system including transmitter electroniccomponents. Interface and control module 26 may include an intrusiondetection module 66 and a compass sensor module 68 of the type disclosedin commonly assigned U.S. Pat. No. 5,255,442 entitled VEHICLE COMPASSWITH ELECTRONIC SENSOR, the disclosure of which is hereby incorporatedherein by reference.

[0033] Interface and control module 26 may be used in combination with asolid-state image capture device 70 of the type disclosed in the PCTInternational patent application filed May 22, 1996, by DonnellyCorporation, Attorney Docket No. DON01 FP-612 (PCT), claiming priorityfrom U.S. patent application Ser. No. 08/445,527 filed May 22, 1995, byKenneth (NMI) Schofield, Mark L. Larson, and Keith I. Vadas for aREARVIEW VISION SYSTEM FOR VEHICLE INCLUDING PANORAMIC VIEW, thedisclosure of which is hereby incorporated herein by reference.Microcomputer 38 may process image data captured by image capture device70 providing a direct communication channel (not shown) to a displaydevice located in and around the vehicle dash. Alternatively,microcomputer 38 may provide data over vehicle-multiplexed communicationbus 30 or rear vision assembly communication channel 28 indicative ofchanges in particular image pixel data, as disclosed in theaforementioned parent application, in order to reduce the amount of datatransmission to the display device.

[0034] An interactive, dynamically adjustable mirror system 80 isprovided in which actuator 40 a and position encoders 42 a and 42 c forreflective elements 44 a and 44 c of driver-side exterior rearviewassembly and passenger-side rearview assembly 20 are provided to acontroller 82 (FIG. 8). A position actuator 40 b and encoder 42 b mayadditionally be provided with the reflective element 44 b of theinterior rearview assembly 18 and interconnected with controller 82(FIG. 8). If it is assumed that the driver's eyes are laterally centeredon an axis C extending through the center of the steering wheel W, anangle θ₁ is formed between the eyes of the driver and the driver-sidemirror element 44 a, an angle θ₂ is formed between the driver's eyes andthe interior reflective element 44 b, and an angle θ₃ is formed betweenthe driver's eyes and the passenger-side exterior reflective element 44c. Assuming that angle β₁ between the vehicle's longitudinal axis andthe field of view observed through the driver-side exterior reflectiveelement is to remain constant, a change in angle θ₁ requires acorresponding change in angle α₁, which is the orientation of thedriver-side exterior reflective element 44 a with respect to a verticalaxis. Likewise, a change in angle θ₂ will require a change in the angleα₂ of interior reflective element 44 b in order to maintain field ofview angle β₂ constant, and a change in angle θ₃ will require a changein the angle of the reflective element 44 c of the passenger-sideexterior mirror in order to maintain the corresponding field of view β₃constant. Utilizing known geometric relationships, a change in any oneof the angles θ₁, θ₂, or θ₃ would provide sufficient information todetermine corresponding changes in the value of the other of the anglesθ₁, θ₂, and θ₃. Likewise, utilizing known geometric relationships,corresponding changes in angles α₁, α₂, and α₃required to compensate forchanges in angles θ₁, θ₂, and θ₃ while keeping the fields of view β₁,β₂, and β₃ constant can be determined. Accordingly, if a change is madein any one of the positional angles α₁, α₂, and α₃, then the necessarychanges to the other of the angles α₁, α₂, and α₃ required tore-establish the desired field of view angles β₁, β₂, and β₃, can bedetermined. In a similar manner, the positional location of reflectiveelements 44 a-44 c about a horizontal axis may be geometrically relatedto the vertical location of the driver's eyes such that a change, forexample, from one driver to another, or a change in the driver's seatelevation, would provide known interrelationships between the relativepositions of the reflective elements with respect to a horizontal axis.This principle is utilized in order to provide an interactiveclosed-loop system which correlates the position of all mirrorreflective elements 44 a-44 c and establishes a particular positionalrelationship between the mirrors. By providing a user input 83 for thedriver to adjust the position of one reflective element 44 a-44 c,interactive mirror system 80 readjusts the positions of the otherreflective elements 44 a-44 c, preferably about both vertical andhorizontal aces, or other pairs of axes, in order to compensate forchanges in the driver's viewing point.

[0035] Changes in the position of the driver's eyes can be determined invarious ways. One manner would be to provide a joystick for user inputselection device 83 to allow the driver to manually adjust the positionof one of the reflective elements. Controller 82 would respond to thechange in position of one of the reflective elements 44 a-44 c byproviding suitable adjustments in the other reflective elements 44 a-44c. Another manner would be to allow the driver to manually position oneof the mirror elements, such as the reflective element associated withthe interior mirror, while monitoring movement of that mirror throughits associated position encoder 42. The resulting change in the positionof the manually adjustable mirror would be processed by controller 82 inorder to provide commensurate changes in the position of the exteriormirror reflective elements. Another technique for determining changes inthe driver's eye location would be to utilize a machine vision system inorder to capture the image of the driver's eyes and determine changes insuch position. Such systems are known in the art.

[0036] Interactive mirror system 80 may additionally include a zeroreset function in order to allow the driver to adjust the relativeposition of any of the reflective elements for a given eye position. Thesystem may further include a lockout feature in order to allow theoperator to lock out the interactive function in order to allow a normalmemory function to occur, as is known in the art. The system mayadditionally provide an override feature to allow the mirror elements inthe system to be independently adjusted.

[0037] An interactive mirror system, according to the invention,provides a unique set of mirror positions for each driver that allowsthe optimum field of view to be provided for that driver to therebyminimize blind spots and provide the driver with the optimal informationon trailing vehicles or when backing the vehicle. In this manner, aninteractive mirror system, according to the invention, not only reducesthe amount of distraction to the driver for repositioning the mirrors,but also improves the performance of the mirror system by overcomingpreconceived notions of drivers as to an optimum position of themirrors.

[0038] Advantageously, an interactive mirror system 80 may utilize arear vision communication system 22 in order to effectively andefficiently communicate control functions among the interior rearviewassembly 18 and the two exterior rearview assemblies 20.

[0039] Changes and modifications in the specifically describedembodiments can be carried out without departing from the principles ofthe invention, which is intended to be limited only by the scope of theappended claims, as interpreted according to the principles of patentlaw including the doctrine of equivalents.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:
 1. A vehicle rear visionsystem for a vehicle having a vehicle communication network, comprising:at least two rearview assemblies, each including an image transferdevice for transferring images rearwardly of the vehicle in order to beobservable by a vehicle driver and a housing for the image transferdevice; and a rear vision communication system providing communicationbetween said rearview assemblies and including a communication link withthe vehicle communication network.
 2. A vehicle rear vision system for avehicle having a vehicle communication network, comprising: at least tworearview assemblies, each including an image transfer device fortransferring images rearwardly of the vehicle in order to be observableby a vehicle driver and a housing for the image transfer device; and arear vision communication system including control modules in saidrearview assemblies interconnected by a communication channel defining arear vision communication network, at least one of said control moduleseffecting communication between said control modules and the vehiclecommunication network.
 3. The rear vision system in claim 2 wherein saidimage transfer device is a mirror.
 4. The rear vision system in claim 3wherein said control modules include control channels which communicatewith at least one of an electro-optic element, a mirror heater, amirror-positioning device, a light-sensing device and a mirror positionencoder.
 5. The rear vision system in claim 3 wherein at least one ofsaid control modules includes control channels which communicate with anelectro-optic element, a mirror heater, a mirror-positioning device anda mirror position encoder.
 6. The rear vision system in claim 3 whereinsaid at least one of said control modules is associated with a vehicleinterior mirror.
 7. The rear vision system in claim 3 wherein said atleast one of said control modules is associated with a vehicle exteriormirror.
 8. The rear vision system in claim 2 wherein at least one ofsaid control modules includes control channels which activate at leastone of a security light positioned in the associated housing and asignal device positioned in the associated housing.
 9. The rear visionsystem in claim 8 wherein said signal device is a turn signal.
 10. Therear vision system in claim 2 wherein at least one of said controlmodules includes control channels which communicate with at least one ofan electromagnetic antenna and a blind spot detector.
 11. The rearvision system in claim 10 wherein said antenna is one of a globalpositioning system antenna, an intelligent vehicle highway systemantenna, cellular telephone antenna, a keyless entry antenna, a garagedoor opener antenna, a radio antenna and a radar antenna.
 12. The rearvision system in claim 2 wherein said image transfer device is asolid-state-imaging array which captures images rearwardly of thevehicle for display by a display device.
 13. The rear vision system inclaim 2 wherein said at least one of said control modules translatesprotocol between the protocol of the vehicle communication network andthe protocol of the rear vision communication network.
 14. The rearvision system in claim 2 wherein said communication channel is abidirectional, serial communication link and each of said controlmodules includes a microprocessor and at least one serial bus data nodeinterfacing said microprocessor to said communication channel.
 15. Therear vision system in claim 14 wherein said at least one of said controlmodules includes a serial bus data node interfacing the associatedmicroprocessor to the vehicle communication network.
 16. The rear visionsystem in claim 2 wherein said at least one of said control modulesincludes a serial bus data node interfacing to the vehicle communicationnetwork.
 17. The rear vision system in claim 2 wherein saidcommunication channel includes one of an electrical conductor, afiber-optic path, a radio frequency link and a carrier-currentmodulation system.
 18. A vehicle rear vision system for a vehicle havinga vehicle communication network, comprising: an interior rearview mirrorassembly and at least one exterior rearview mirror assembly, eachincluding an electro-optic reflective element and a housing for thereflective element; said interior rearview mirror assembly including amicroprocessor-based control having a control channel to establish apartial reflectance level of the associated electro-optic reflectiveelement; said at least one exterior rearview mirror assembly including amicroprocessor-based control having a first control channel to establisha partial reflectance level of the associated electro-optic reflectiveelement, a second control channel to selectively activate a heaterelement in heat transfer association with the associated electro-opticreflective element, a third control channel to operate a positioningdevice for the associated electro-optic reflective element and a fourthcontrol channel for receiving positional data from an encoder coupledwith the associated electro-optic reflective element; and acommunication channel interconnecting said microprocessor-based controlsdefining a rear vision communication network; wherein one of saidmicroprocessor-based controls includes a hardware node configured tointerconnect with the vehicle communication network and is programmed toformat messages for the vehicle communication network and decodemessages from the vehicle communication network.
 19. The rear visionsystem in claim 18 wherein said at least one exterior rearview mirrorassembly includes two exterior rearview mirror assemblies, eachincluding a microprocessor-based control having a first control channelto establish a partial reflectance level of the associated electro-opticreflective element, a second control channel to selectively activate aheater element in heat transfer association with the associatedelectro-optic reflective element, a third control channel to operate apositioning device for the associated electro-optic reflective elementand a fourth control channel for receiving positional data from anencoder coupled with the associated electro-optic reflective element;wherein said communication channel interconnects saidmicroprocessor-based controls of said interior rearview mirror assemblyand said two exterior rearview mirror assemblies.
 20. The rear visionsystem in claim 18 wherein said one of said microprocessor-basedcontrols translates protocol between the protocol of the vehiclecommunication network and the-protocol of the rear vision communicationnetwork.
 21. The rear vision system in claim 18 wherein said one of saidmicroprocessor-based controls is associated with said vehicle interiorrearview mirror assembly.
 22. The rear vision system in claim 18 whereinsaid one of said microprocessor-based controls is associated with saidat least one vehicle exterior rearview mirror assembly.
 23. The rearvision system in claim 18 wherein said communication channel is abidirectional, serial communication link and each of saidmicroprocessor-based controls includes at least one serial bus data nodeinterfacing said microprocessor to said communication channel.
 24. Avehicle rear vision system, comprising: a plurality of rearview mirrorassemblies, each including a reflective element, an actuator whichadjustably positions said reflective element about at least one axis anda position encoder which monitors the position of said reflectiveelement with respect to said at least one axis; and a control which isresponsive to said encoder for each mirror assembly in order to supplysignals to the actuator for that mirror assembly to adjust the positionof the associated reflective element of that mirror assembly, at leastas a function of the position of the associated reflective element ofthat mirror assembly and the position of the reflective element of atleast one other of said mirror assemblies.
 25. The rear vision system inclaim 24 including a user adjustable input device in order to supplysignals to the actuator for the reflective element of said other of saidmirror assemblies to adjust the position of the reflective element ofthat other of said mirror assemblies.
 26. The rear vision system inclaim 25 wherein said input device is a user manipulable joystick. 27.The rear vision system in claim 25 wherein said input device is a usermanipulable switching device.
 28. The rear vision system in claim 25wherein said input device is an encoder mechanically coupled with amanually positionable reflective element.
 29. The rear vision system inclaim 25 wherein said input device is a machine vision system whichmonitors the position of the eyes of a vehicle driver.
 30. The rearvision system in claim 24 including a lockout device to lock out saidcontrol.
 31. The rear vision system in claim 24 including a zero-setdevice to set a zero position for the associated reflective element ofthat mirror assembly.
 32. A vehicle rear vision system, comprising: aplurality of rearview mirror assemblies, each including a reflectiveelement, an actuator which adjustably positions said reflective elementabout at least one axis and a position encoder which monitors theposition of said reflective element with respect to said at least oneaxis; and a control which is responsive to said encoder for each mirrorassembly to adjust the positions of said plurality of mirror assembliesin a manner which causes said reflective elements to remain aimed at acommon location substantially irrespective of movement of said commonlocation.
 33. The rear vision system in claim 32 including a useradjustable input device in order to adjust said common location.
 34. Therear vision system in claim 33 wherein said input device is a usermanipulable joystick.
 35. The rear vision system in claim 33 whereinsaid input device is a user manipulable switching device.
 36. The rearvision system in claim 33 wherein said input device is an encodermechanically coupled with a manually positionable reflective element.37. The rear vision system in claim 33 wherein said input device is amachine vision system which monitors the position of the eyes of avehicle driver.
 38. The rear vision system in claim 32 wherein saidcommon location is defined with respect to a given vertical plane and agiven horizontal plane.